The reason late night anime are aired late at night is because of their limited mainstream interest, not because of adult themes. Late night ecchi anime are censored for the sole reason of pushing disc sales, nothing else.

The same could in theory be argued about manga serializations and tankoubon, but apparently that marketing tactic hasn't yet caught on for print media to the same extent as with anime. TLR did have instances of that happening to it in the past though.

Anyway, age restrictions never had anything to do with it in either case. Reduced to what it boils down to in practice, if it doesn't show genitals in plain (pixelated) sight during explicit sexual acts, it's all-ages. Regardless of medium.

Because she is the only human child (loli) in this series that show her nakedness, remember, she is still a elementary schooler. Yami, Momo and Nana maybe have thousand of years by all what we know, and showing girls over 15 years old totally naked is perfectly fine, it no matter how they look

Why not just make a To Love Ru Hentai series? I never understood why the author would just draw these girls fully naked but cover them up, and not have sex scenes...that's just what the creepy otakus want so why not just do that?

Lemme guess somehow Yami places the blame on Rito and hits him? Let's face it she has the potential to be more than this two dimensional persona she's been given, its rather redundant is causing her to lose any charm she has as a character. Though I suppose the large harem theme is partly to blame as a large roster of characters can wear diversity somewhat thin.